Browsing by Subject "Ligand"

Now showing 1 - 3 of 3

Open Access
Immunization with UV-induced apoptotic cells generates monoclonal antibodies against proteins differentially expressed in hepatocellular carcinoma cell lines
(Mary Ann Liebert, Inc, 2007) Celikkaya, H.; Ciraci, C.; Oztas, E.; Avci, M. E.; Ozturk, M.; Yagci, T.
Early and differential diagnosis of hepatocellular carcinoma (HCC) requires sensitive and specific tissue and serum markers. On the other hand, proteins involved in tumorigenesis are extensively modelated on exposure to apoptotic stimuli, including ultraviolet (UVC) irradiation. Hence, we generated monoclonal antibodies by using UVC-irradiated apoptotic cells of an HCC cell line, HUH7, aiming to explore proteins differentially expressed in tumors and apoptosis. We obtained 18 hybridoma clones recognizing protein targets in apoptotic HUH7 cells, and clone 6D5 was chosen for characterization studies because of its strong reactivity in cell-ELISA assay. Subtype of the antibody was IgG3 (κ). Targets of 6D5 antibody were found to be abundantly expressed in all HCC cell lines except FLC4, which resembles normal hepatocytes. We also observed the secretion of 6D5 ligands by some of the HCC cell lines. Moreover, cellular proteins recognized by the antibody displayed a late upregulation in UVC-induced apoptotic cells. We concluded that 6D5 target proteins are modulated in liver tumorigenesis and apoptotic processes. We therefore propose the validation of our antibody in tissue and serum samples of HCC patients to assess its potential use for the early diagnosis of HCC and to understand the role of 6D5 ligands in liver carcinogenesis. © Mary Ann Liebert, Inc.
Open Access
Impaired toll like receptor-7 and 9 induced immune activation in chronic spinal cord injured patients contributes to immune dysfunction
(Public Library of Science, 2017) Gucluler, G.; Adiguzel, E.; Gungor, B.; Kahraman, T.; Gursel, M.; Yilmaz, B.; Gursel, I.
Reduced immune activation or immunosuppression is seen in patients withneurological diseases. Urinary and respiratory infections mainly manifested as septicemia and pneumonia are the most frequent complications following spinal cord injuries and they account for the majority of deaths. The underlying reason of these losses is believed to arise due to impaired immune responses to pathogens. Here, we hypothesized that susceptibility to infections of chronic spinal cord injured (SCI) patients might be due to impairment in recognition of pathogen associated molecular patterns and subsequently declining innate and adaptive immune responses that lead to immune dysfunction. We tested our hypothesis on healthy and chronic SCI patients with a level of injury above T-6. Donor PBMCs were isolated and stimulated with different toll like receptor ligands and T-cell inducers aiming to investigate whether chronic SCI patients display differential immune activation to multiple innate and adaptive immune cell stimulants. We demonstrate that SCI patients' B-cell and plasmacytoid dendritic cells retain their functionality in response to TLR7 and TLR9 ligand stimulation as they secreted similar levels of IL6 and IFNα. The immune dysfunction is not probably due to impaired T-cell function, since neither CD4+ T-cell dependent IFNγ producing cell number nor IL10 producing regulatory T-cells resulted different outcomes in response to PMA-Ionomycin and PHA-LPS stimulation, respectively. We showed that TLR7 dependent IFNγ and IP10 levels and TLR9 mediated APC function reduced substantially in SCI patients compared to healthy subjects. More importantly, IP10 producing monocytes were significantly fewer compared to healthy subjects in response to TLR7 and TLR9 stimulation of SCI PBMCs. When taken together this work implicated that these defects could contribute to persistent complications due to increased susceptibility to infections of chronic SCI patients. © 2017 Gucluler et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Open Access
Redundant expression of canonical Wnt ligands in human breast cancer cell lines
(Spandidos Publications Ltd., 2006) Benhaj, K.; Akcali, K. C.; Ozturk, M.
Human breast cancer displays nuclear accumulation of β-catenin and induction of cyclin D1 expression, which suggests that canonical Wnt/β-catenin signaling is activated. In other cancers, the activation of canonical wnt/β-catenin signaling is associated with APC, CTNNB1 or AXIN1 mutations. However, these mutations are rare or absent in breast cancer. In search of alternative mechanisms, we performed comprehensive expression analysis of Wnt signaling molecules, including 19 Wnt ligands, ten Frizzled receptors, two co-receptors and four Lef/TCF transcription factors in immortalized normal human mammary epithelial cells (HMEC) and six breast cancer cell lines. HMEC expressed all Frizzled receptors except FZD9 and FZD10. They also expressed LRP5 and LRP6 co-receptors, as well as four Lef/TCF transcription factors. HMEC cells also expressed many Wnt ligands, including WNT1, WNT2B, WNT3, WNT5A, WNT5B, WNT7B, WNT9A, WNT10B and WNT16 . Redundant expression of Wnt ligands, Frizzled receptors, co-receptors and Lef/TCF transcription factors was maintained in breast cancer cell lines with some exceptions. The most important changes in cancer cell lines concerned Wnt ligand expression. We noticed that most breast cancer cell lines overexpressed WNT3A, WNT4, WNT6, WNT8B, WNT9A and WNT10B. In contrast, the expression of WNT5A, WNT5B and WNT16 was usually down-regulated. It is noteworthy that all six Wnt ligands that are overexpressed in malignant cell lines are known to signal through the canonical Wnt/β-catenin signaling pathway, whereas down-regulated WNT5A and WNT5B ligands signal via the non-canonical pathway. The expression of both canonical Wnt ligands and most Frizzled receptors in breast cancer cell lines suggests that canonical Wnt/β-catenin signaling is activated in these cell lines by an autocrine/paracrine mechanism. In support of this prediction, we observed nuclear β-catenin accumulation and cyclin D1 induction in breast cancer cell lines, but not in HMEC. These results imply that ligand-dependent canonical Wnt/β-catenin signaling is active in human breast cancer.